title: HIV-1 infected monozygotic twins: a tale of two outcomes.
abstract: BACKGROUND
  Replicate experiments are often difficult to find in evolutionary biology, as this field is inherently an historical science. However, viruses, bacteria and phages provide opportunities to study evolution in both natural and experimental contexts, due to their accelerated rates of evolution and short generation times. Here we investigate HIV-1 evolution by using a natural model represented by monozygotic twins infected synchronically at birth with an HIV-1 population from a shared blood transfusion source. We explore the evolutionary processes and population dynamics that shape viral diversity of HIV in these monozygotic twins.
  
  
  RESULTS
  Despite the identical host genetic backdrop of monozygotic twins and the identical source and timing of the HIV-1 inoculation, the resulting HIV populations differed in genetic diversity, growth rate, recombination rate, and selection pressure between the two infected twins.
  
  
  CONCLUSIONS
  Our study shows that the outcome of evolution is strikingly different between these two "replicates" of viral evolution. Given the identical starting points at infection, our results support the impact of random epigenetic selection in early infection dynamics. Our data also emphasize the need for a better understanding of the impact of host-virus interactions in viral evolution.
authors.affiliation: Division of Epidemiology, Human Genetics and Environmental Sciences, University of Texas, Health Science Center at Houston, School of Public Health, Brownsville, TX, USA. Loubna.Tazi@uth.tmc.edu
authors.forename: Loubna
authors.initials: L
authors.lastname: Tazi
authors.forename: Hiromi
authors.initials: H
authors.lastname: Imamichi
authors.forename: Steven
authors.initials: S
authors.lastname: Hirschfeld
authors.forename: Julia A
authors.initials: JA
authors.lastname: Metcalf
authors.forename: Susan
authors.initials: S
authors.lastname: Orsega
authors.forename: Marcos
authors.initials: M
authors.lastname: Pérez-Losada
authors.forename: David
authors.initials: D
authors.lastname: Posada
authors.forename: H Clifford
authors.initials: HC
authors.lastname: Lane
authors.forename: Keith A
authors.initials: KA
authors.lastname: Crandall
mesh_terms: D004200:Diseases in Twins / Q000821:virology*; D019143:Evolution, Molecular; D014644:Genetic Variation; D015658:HIV Infections / Q000821:virology*; D015497:HIV-1 / Q000235:genetics*; D006801:Humans; D008297:Male; D010802:Phylogeny; D011157:Population Dynamics; D012367:RNA, Viral / Q000235:genetics; D017423:Sequence Analysis, RNA; D014430:Twins, Monozygotic
chemical_list: D012367:RNA, Viral